package com.mayavi.enums;
import java.io.Serializable;
import java.lang.reflect.Method;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;

import org.hibernate.HibernateException;
import org.hibernate.type.NullableType;
import org.hibernate.type.TypeFactory;
import org.hibernate.usertype.ParameterizedType;
import org.hibernate.usertype.UserType;

public class EnumUserType implements UserType, ParameterizedType {
	private static final String DEFAULT_IDENTIFIER_METHOD_NAME = "name";
	private static final String DEFAULT_VALUE_OF_METHOD_NAME = "valueOf";

	protected static final String IDENTIFIER_METHOD = "identifierMethod";
	protected static final String VALUEOF_METHOD = "valueOfMethod";

	@SuppressWarnings("unchecked")
	private Class<? extends Enum> enumClass;
	private Class<?> identifierType;
	private Method identifierMethod;
	private Method valueOfMethod;
	private NullableType type;
	private int[] sqlTypes;

	public void setParameterValues(final Properties parameters) {
		final String enumClassName = parameters.getProperty("enumClass");
		try {
			enumClass = Class.forName(enumClassName).asSubclass(Enum.class);
		} catch (final ClassNotFoundException cfne) {
			throw new HibernateException("Enum class not found", cfne);
		}

		final String identifierMethodName = parameters
				.getProperty(IDENTIFIER_METHOD, DEFAULT_IDENTIFIER_METHOD_NAME);

		try {
			identifierMethod = enumClass.getMethod(identifierMethodName, new Class[0]);
			identifierType = identifierMethod.getReturnType();
		} catch (final Exception e) {
			throw new HibernateException("Failed to obtain identifier method", e);
		}

		type = (NullableType) TypeFactory.basic(identifierType.getName());

		if (type == null) {
			throw new HibernateException("Unsupported identifier type " + identifierType.getName());
		}

		sqlTypes = new int[] { type.sqlType() };

		final String valueOfMethodName = parameters
				.getProperty(VALUEOF_METHOD, DEFAULT_VALUE_OF_METHOD_NAME);

		try {
			valueOfMethod = enumClass.getMethod(valueOfMethodName, new Class[] { identifierType });
		} catch (final Exception e) {
			throw new HibernateException("Failed to obtain valueOf method", e);
		}
	}

	public Class<?> returnedClass() {
		return enumClass;
	}

	public Object nullSafeGet(final ResultSet rs, final String[] names, final Object owner) throws HibernateException, SQLException {
		final Object identifier = type.get(rs, names[0]);
		if (rs.wasNull()) {
			return null;
		}

		try {
			return valueOfMethod.invoke(enumClass, new Object[] { identifier });
		} catch (final Exception e) {
			throw new HibernateException("Exception while invoking valueOf method '"
					+ valueOfMethod.getName() + "' of " + "enumeration class '" + enumClass + "'", e);
		}
	}

	public void nullSafeSet(final PreparedStatement st, final Object value, final int index) throws HibernateException, SQLException {
		try {
			if (value == null) {
				st.setNull(index, type.sqlType());
			} else {
				final Object identifier = identifierMethod.invoke(value, new Object[0]);
				type.set(st, identifier, index);
			}
		} catch (final Exception e) {
			throw new HibernateException("Exception while invoking identifierMethod '"
					+ identifierMethod.getName() + "' of " + "enumeration class '" + enumClass
					+ "'", e);
		}
	}

	public int[] sqlTypes() {
		return sqlTypes;
	}

	public Object assemble(final Serializable cached, final Object owner) throws HibernateException {
		return cached;
	}

	public Object deepCopy(final Object value) throws HibernateException {
		return value;
	}

	public Serializable disassemble(final Object value) throws HibernateException {
		return (Serializable) value;
	}

	public boolean equals(final Object x, final Object y) throws HibernateException {
		return x == y;
	}

	public int hashCode(final Object x) throws HibernateException {
		return x.hashCode();
	}

	public boolean isMutable() {
		return false;
	}

	public Object replace(final Object original, final Object target, final Object owner) throws HibernateException {
		return original;
	}
}
